Ok Ace. What do you need for the flow test on my cylinder head? Send me off a e-mail, its in my profile. Hitchcock's has a 10% discount this weekend, gonna order a crank. Any idea which one I need? I sent them off a e-mail, they offer:

Ok Ace. What do you need for the flow test on my cylinder head? Send me off a e-mail, its in my profile. Hitchcock's has a 10% discount this weekend, gonna order a crank. Any idea which one I need? I sent them off a e-mail, they offer:

My bike is a 2001 Kickstart only Export 500. I do run a total loss electrical system, but I do use a crank triggered ignition in the rotor mounting keyway.

Okay Westie.It's #200160 metric Indian type. Specify kickstart only when ordering.Probably wouldn't hurt to order a new engine sprocket for the primary, and have them check it on the shaft splines to be sure it fits right, when you make the order.There are some issues with the splines and some gears from other year engines.

This head is really flowing well with these latest mods.Everything is doing even better than expected.I think this engine is going to make huge power.

I'm really really happy with what I'm seeing so far from this project!

Thanks for the update, Ace, that sounds very promising! Hopefully, work will soon begin on what changes we will implement below the cylinder head level of this engine Without 'spilling any beans', but as a point of interest and maybe reference, the highest figure we ever recorded, on what appears to be an exceptional day as far as favourable conditions go, from the 500 was 45.95 bhp. On the same Dynojet dyno and on the same day, the 350 recorded 37.13 bhp. These figures remain an all time best for both our racers. That dyno [and the entire bike shop] were destroyed in a terrible fire soon after that, meaning we were forced into using another Dynojet dyno a little further away from us and this seems to use about 3 bhp more from any machine we put on it, by comparison. The best we have seen from the 500 on this dyno is around 42 bhp and the 350 manages around 33 bhp. A Crusader belonging to Steve Cotrell, which we also race, came down from 28.5 bhp to just short of 25 bhp on this dyno, while a Kawasaki ZXR 400 lost 3-4 bhp as well. This will be the dyno we will test the reworked 500 engine on and the 350 will continue with last year's short rod engine, so this machine could give us some sort of benchmark or 'constant'. If this shows 32 / 33 bhp on the day, anything over 42 bhp from the 500 will be going the right way. B.W.

Thanks for sharing the info on hp from the past dyno runs, Paul!This gives me a nice lead-in for a technical post on how this all comes together to get results.

We have just seen some horsepower figures on Paul's racing engines. and we have also seen first-hand information that dynos are not all the same, so their main function is for a comparison basis of the same bike on the same dyno.Now, what is horsepower? We talk about it a lot, but do we really know what it is?It's a measurement of work.

Horsepower is comprised of torque and rpm(rotations per minute) of the engine.Torque is defined as how much force can be applied to the crankshaft by the engine in one "push" of the piston. It's "how hard" it can push.But, we need to do more than one push, and we need to push it far, in order to do our work.So, we push the piston down a lot of times over a time period like a minute, and then we get a push(torque force) times the revolutions of the engine over the time span of a minute(rpm), and then divide by a mathematical constant(5252), and that gives us horsepower.Tq x Rpm/5252 = Hp

In short, horsepower is what we get when we push the piston down a whole bunch of times during a minute, and that gives us the amount of work we can do. If we have just one amount of force pushing down each time, then the more times we can push it down in a minute, we will get more horsepower to do our work. And if we can push it down harder to get more force, then taht will also give us more horsepower to do our work.So, to get more horsepower, we want to increase how hard we can push the piston down, and also increase the number of times per minute that we can do it.

Okay. So, big deal. Everybody knows that, right?All right.

So, this is where the tech stuff starts. How are we going to get more "push", and how are we going to get more rpms?Well, to get to the meat of the issue, to get more "push" we need to get better cylinder filling, so that the engine can operate at highest efficiency. So, it needs air flow.And, as the rpms get faster and faster, there is less time for the air to get into the cylinder, so it is likely that less will get in. And, when it's enough less getting in to not be able to produce any more power, then the engine will not be able to productively rev any higher, or make any higher power. It's the amount of air getting in that makes the limits.

How can we improve it?Well, the main methods are to open the valves higher, and to hold the valves open longer for more time for the air to flow in at higher rpms, and also to make the sizes of the valves and ports(also shape of ports) correct to get more air flow in during the same amount of time. So, this is why we talk about valve lift, and duration, and how much cfm(cubic feet per minute) of air the inlet system can deliver. The more cfm it can deliver, then the better it can fill the cylinder in less time. The longer the valves are open, the more air can get in per revolution. The higher the valves are lifted, the more air can get in(assuming the port is done to match). These are our methods. There's a lot of high tech processes in doing this, but at the basic level, these are the things we are doing.

We are going to open those valves a lot further, and we are increasing the port air flow to take the best advantage of those higher-lifted valves, and we are going to hold those higher-lifted valves open for a longer time than before. The goal is to keep getting enough air in there to fill that cylinder really full in a very short period of time, for a much higher engine speed(rpm) so that we get more "push", and hold on to it for a much higher rpm speed, so that we make a significant amount more horsepower.